FIELD OF THE INVENTION
The present invention relates to a cooker, and more particularly to a cooker using a self-induced heating method wherein a thermistor is provided for sensing surface temperature of a cooker pad plate.
A cooker using a self-induced heating method directly heats a metal utensil with a loss of eddy current flowing in the working coil (heating coil) attached to the coil pad plate.
A thermistor type of temperature sensing element is disposed on this cooker in order to control the coil according to the sensed temperatures.
The thermistor is closely disposed to a top plate for supporting the cooking utensils in order to sense temperatures of the utensils more accurately.
For example, a Japanese laid open patent application No. Sho 62(1987)-143387 entitled, "electronically-induced heating cooker" discloses a cooker wherein a heating coil is installed, a top plate is disposed on a top area to support a cooking utensil, and a temperature sensor for sensing a temperature in the cooking utensil is disposed on the top plate.
Depicted in FIG. 7 is a cooker described in Japanse laid open patent application No. Sho 62(1987)-143387, the cooker including a temperature sensor 16 wherein a thermistor 15 is sealed in a conductive metal case 14 that is disposed on a top plate 12,
Also depicted in FIG. 7 is a main body 9 of the electronically-induced heating cooker, a heating coil 10, a control unit 11, a recess 13, a cooking utensil 17 and a kitchen counter top 18. In the cooker thus constructed, the thermistor conventionally detects temperature transmitted from the cooking utensil through the top plate, and a control unit of the cooker, once the temperature detected by the temperature sensor rises above a firstly-designated temperature (approximately 320.degree. C.), stops operation of the cooker.
The control unit of the cooker re-operates the cooker once the temperature is below a secondly-designated temperature (approximately 200.degree. C.)
Meanwhile, when an interior of the cooker is overheated due to a malfunctioning of the thermistor and the like, wirings and elements in the interior are sure to be harmed, so that a thermal fuse is inevitably equipped in order to prevent the overheating.
The thermal fuse is rendered open when the interior temperature rises above a predetermined temperature (approximately 130.degree. C.) to thereby cut off the power being inputted to the heating (working) coil.
As mentioned above, in the case of a cooker, one coil pad plate disposed with the working coil cannot carry the thermistor and the thermal fuse at the same time, to thereby necessitate a separate attachment apparatus and complicate the assembly process.
Furthermore, because the working coil is usually attached to the coil pad plate of the cooker by adhesives such as epoxy and the like, the working coil tends to separate from the coil pad plate due to the heat generated by the operation of the cooker.
In order to prevent the separation of the working coil from the plate, a separate support has been used to pressingly fix the working coil.
However, because the support can only press to an outside portion of the cooking coil, there is a problem in that the interior portion of the coil tends to be separated by high heat during cooking.
In order to solve the inside portion of the above problems, a separate apparatus is needed for fixing the working coil, which consequently increases the number of parts to thereby result in difficulty in assembly and reduced manufacturing productivity.